Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1159 insertions, 0 deletions

diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
new file mode 100644
index 0000000000..f9a419cd22
--- /dev/null
+++ b/kernel/kexec_file.c
@@ -0,0 +1,1159 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * kexec: kexec_file_load system call
+ *
+ * Copyright (C) 2014 Red Hat Inc.
+ * Authors:
+ *      Vivek Goyal <vgoyal@redhat.com>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/capability.h>
+#include <linux/mm.h>
+#include <linux/file.h>
+#include <linux/slab.h>
+#include <linux/kexec.h>
+#include <linux/memblock.h>
+#include <linux/mutex.h>
+#include <linux/list.h>
+#include <linux/fs.h>
+#include <linux/ima.h>
+#include <crypto/hash.h>
+#include <crypto/sha2.h>
+#include <linux/elf.h>
+#include <linux/elfcore.h>
+#include <linux/kernel.h>
+#include <linux/kernel_read_file.h>
+#include <linux/syscalls.h>
+#include <linux/vmalloc.h>
+#include "kexec_internal.h"
+
+#ifdef CONFIG_KEXEC_SIG
+static bool sig_enforce = IS_ENABLED(CONFIG_KEXEC_SIG_FORCE);
+
+void set_kexec_sig_enforced(void)
+{
+	sig_enforce = true;
+}
+#endif
+
+static int kexec_calculate_store_digests(struct kimage *image);
+
+/* Maximum size in bytes for kernel/initrd files. */
+#define KEXEC_FILE_SIZE_MAX	min_t(s64, 4LL << 30, SSIZE_MAX)
+
+/*
+ * Currently this is the only default function that is exported as some
+ * architectures need it to do additional handlings.
+ * In the future, other default functions may be exported too if required.
+ */
+int kexec_image_probe_default(struct kimage *image, void *buf,
+			      unsigned long buf_len)
+{
+	const struct kexec_file_ops * const *fops;
+	int ret = -ENOEXEC;
+
+	for (fops = &kexec_file_loaders[0]; *fops && (*fops)->probe; ++fops) {
+		ret = (*fops)->probe(buf, buf_len);
+		if (!ret) {
+			image->fops = *fops;
+			return ret;
+		}
+	}
+
+	return ret;
+}
+
+static void *kexec_image_load_default(struct kimage *image)
+{
+	if (!image->fops || !image->fops->load)
+		return ERR_PTR(-ENOEXEC);
+
+	return image->fops->load(image, image->kernel_buf,
+				 image->kernel_buf_len, image->initrd_buf,
+				 image->initrd_buf_len, image->cmdline_buf,
+				 image->cmdline_buf_len);
+}
+
+int kexec_image_post_load_cleanup_default(struct kimage *image)
+{
+	if (!image->fops || !image->fops->cleanup)
+		return 0;
+
+	return image->fops->cleanup(image->image_loader_data);
+}
+
+/*
+ * Free up memory used by kernel, initrd, and command line. This is temporary
+ * memory allocation which is not needed any more after these buffers have
+ * been loaded into separate segments and have been copied elsewhere.
+ */
+void kimage_file_post_load_cleanup(struct kimage *image)
+{
+	struct purgatory_info *pi = &image->purgatory_info;
+
+	vfree(image->kernel_buf);
+	image->kernel_buf = NULL;
+
+	vfree(image->initrd_buf);
+	image->initrd_buf = NULL;
+
+	kfree(image->cmdline_buf);
+	image->cmdline_buf = NULL;
+
+	vfree(pi->purgatory_buf);
+	pi->purgatory_buf = NULL;
+
+	vfree(pi->sechdrs);
+	pi->sechdrs = NULL;
+
+#ifdef CONFIG_IMA_KEXEC
+	vfree(image->ima_buffer);
+	image->ima_buffer = NULL;
+#endif /* CONFIG_IMA_KEXEC */
+
+	/* See if architecture has anything to cleanup post load */
+	arch_kimage_file_post_load_cleanup(image);
+
+	/*
+	 * Above call should have called into bootloader to free up
+	 * any data stored in kimage->image_loader_data. It should
+	 * be ok now to free it up.
+	 */
+	kfree(image->image_loader_data);
+	image->image_loader_data = NULL;
+}
+
+#ifdef CONFIG_KEXEC_SIG
+#ifdef CONFIG_SIGNED_PE_FILE_VERIFICATION
+int kexec_kernel_verify_pe_sig(const char *kernel, unsigned long kernel_len)
+{
+	int ret;
+
+	ret = verify_pefile_signature(kernel, kernel_len,
+				      VERIFY_USE_SECONDARY_KEYRING,
+				      VERIFYING_KEXEC_PE_SIGNATURE);
+	if (ret == -ENOKEY && IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING)) {
+		ret = verify_pefile_signature(kernel, kernel_len,
+					      VERIFY_USE_PLATFORM_KEYRING,
+					      VERIFYING_KEXEC_PE_SIGNATURE);
+	}
+	return ret;
+}
+#endif
+
+static int kexec_image_verify_sig(struct kimage *image, void *buf,
+				  unsigned long buf_len)
+{
+	if (!image->fops || !image->fops->verify_sig) {
+		pr_debug("kernel loader does not support signature verification.\n");
+		return -EKEYREJECTED;
+	}
+
+	return image->fops->verify_sig(buf, buf_len);
+}
+
+static int
+kimage_validate_signature(struct kimage *image)
+{
+	int ret;
+
+	ret = kexec_image_verify_sig(image, image->kernel_buf,
+				     image->kernel_buf_len);
+	if (ret) {
+
+		if (sig_enforce) {
+			pr_notice("Enforced kernel signature verification failed (%d).\n", ret);
+			return ret;
+		}
+
+		/*
+		 * If IMA is guaranteed to appraise a signature on the kexec
+		 * image, permit it even if the kernel is otherwise locked
+		 * down.
+		 */
+		if (!ima_appraise_signature(READING_KEXEC_IMAGE) &&
+		    security_locked_down(LOCKDOWN_KEXEC))
+			return -EPERM;
+
+		pr_debug("kernel signature verification failed (%d).\n", ret);
+	}
+
+	return 0;
+}
+#endif
+
+/*
+ * In file mode list of segments is prepared by kernel. Copy relevant
+ * data from user space, do error checking, prepare segment list
+ */
+static int
+kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
+			     const char __user *cmdline_ptr,
+			     unsigned long cmdline_len, unsigned flags)
+{
+	ssize_t ret;
+	void *ldata;
+
+	ret = kernel_read_file_from_fd(kernel_fd, 0, &image->kernel_buf,
+				       KEXEC_FILE_SIZE_MAX, NULL,
+				       READING_KEXEC_IMAGE);
+	if (ret < 0)
+		return ret;
+	image->kernel_buf_len = ret;
+
+	/* Call arch image probe handlers */
+	ret = arch_kexec_kernel_image_probe(image, image->kernel_buf,
+					    image->kernel_buf_len);
+	if (ret)
+		goto out;
+
+#ifdef CONFIG_KEXEC_SIG
+	ret = kimage_validate_signature(image);
+
+	if (ret)
+		goto out;
+#endif
+	/* It is possible that there no initramfs is being loaded */
+	if (!(flags & KEXEC_FILE_NO_INITRAMFS)) {
+		ret = kernel_read_file_from_fd(initrd_fd, 0, &image->initrd_buf,
+					       KEXEC_FILE_SIZE_MAX, NULL,
+					       READING_KEXEC_INITRAMFS);
+		if (ret < 0)
+			goto out;
+		image->initrd_buf_len = ret;
+		ret = 0;
+	}
+
+	if (cmdline_len) {
+		image->cmdline_buf = memdup_user(cmdline_ptr, cmdline_len);
+		if (IS_ERR(image->cmdline_buf)) {
+			ret = PTR_ERR(image->cmdline_buf);
+			image->cmdline_buf = NULL;
+			goto out;
+		}
+
+		image->cmdline_buf_len = cmdline_len;
+
+		/* command line should be a string with last byte null */
+		if (image->cmdline_buf[cmdline_len - 1] != '\0') {
+			ret = -EINVAL;
+			goto out;
+		}
+
+		ima_kexec_cmdline(kernel_fd, image->cmdline_buf,
+				  image->cmdline_buf_len - 1);
+	}
+
+	/* IMA needs to pass the measurement list to the next kernel. */
+	ima_add_kexec_buffer(image);
+
+	/* Call image load handler */
+	ldata = kexec_image_load_default(image);
+
+	if (IS_ERR(ldata)) {
+		ret = PTR_ERR(ldata);
+		goto out;
+	}
+
+	image->image_loader_data = ldata;
+out:
+	/* In case of error, free up all allocated memory in this function */
+	if (ret)
+		kimage_file_post_load_cleanup(image);
+	return ret;
+}
+
+static int
+kimage_file_alloc_init(struct kimage **rimage, int kernel_fd,
+		       int initrd_fd, const char __user *cmdline_ptr,
+		       unsigned long cmdline_len, unsigned long flags)
+{
+	int ret;
+	struct kimage *image;
+	bool kexec_on_panic = flags & KEXEC_FILE_ON_CRASH;
+
+	image = do_kimage_alloc_init();
+	if (!image)
+		return -ENOMEM;
+
+	image->file_mode = 1;
+
+	if (kexec_on_panic) {
+		/* Enable special crash kernel control page alloc policy. */
+		image->control_page = crashk_res.start;
+		image->type = KEXEC_TYPE_CRASH;
+	}
+
+	ret = kimage_file_prepare_segments(image, kernel_fd, initrd_fd,
+					   cmdline_ptr, cmdline_len, flags);
+	if (ret)
+		goto out_free_image;
+
+	ret = sanity_check_segment_list(image);
+	if (ret)
+		goto out_free_post_load_bufs;
+
+	ret = -ENOMEM;
+	image->control_code_page = kimage_alloc_control_pages(image,
+					   get_order(KEXEC_CONTROL_PAGE_SIZE));
+	if (!image->control_code_page) {
+		pr_err("Could not allocate control_code_buffer\n");
+		goto out_free_post_load_bufs;
+	}
+
+	if (!kexec_on_panic) {
+		image->swap_page = kimage_alloc_control_pages(image, 0);
+		if (!image->swap_page) {
+			pr_err("Could not allocate swap buffer\n");
+			goto out_free_control_pages;
+		}
+	}
+
+	*rimage = image;
+	return 0;
+out_free_control_pages:
+	kimage_free_page_list(&image->control_pages);
+out_free_post_load_bufs:
+	kimage_file_post_load_cleanup(image);
+out_free_image:
+	kfree(image);
+	return ret;
+}
+
+SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
+		unsigned long, cmdline_len, const char __user *, cmdline_ptr,
+		unsigned long, flags)
+{
+	int image_type = (flags & KEXEC_FILE_ON_CRASH) ?
+			 KEXEC_TYPE_CRASH : KEXEC_TYPE_DEFAULT;
+	struct kimage **dest_image, *image;
+	int ret = 0, i;
+
+	/* We only trust the superuser with rebooting the system. */
+	if (!kexec_load_permitted(image_type))
+		return -EPERM;
+
+	/* Make sure we have a legal set of flags */
+	if (flags != (flags & KEXEC_FILE_FLAGS))
+		return -EINVAL;
+
+	image = NULL;
+
+	if (!kexec_trylock())
+		return -EBUSY;
+
+	if (image_type == KEXEC_TYPE_CRASH) {
+		dest_image = &kexec_crash_image;
+		if (kexec_crash_image)
+			arch_kexec_unprotect_crashkres();
+	} else {
+		dest_image = &kexec_image;
+	}
+
+	if (flags & KEXEC_FILE_UNLOAD)
+		goto exchange;
+
+	/*
+	 * In case of crash, new kernel gets loaded in reserved region. It is
+	 * same memory where old crash kernel might be loaded. Free any
+	 * current crash dump kernel before we corrupt it.
+	 */
+	if (flags & KEXEC_FILE_ON_CRASH)
+		kimage_free(xchg(&kexec_crash_image, NULL));
+
+	ret = kimage_file_alloc_init(&image, kernel_fd, initrd_fd, cmdline_ptr,
+				     cmdline_len, flags);
+	if (ret)
+		goto out;
+
+	ret = machine_kexec_prepare(image);
+	if (ret)
+		goto out;
+
+	/*
+	 * Some architecture(like S390) may touch the crash memory before
+	 * machine_kexec_prepare(), we must copy vmcoreinfo data after it.
+	 */
+	ret = kimage_crash_copy_vmcoreinfo(image);
+	if (ret)
+		goto out;
+
+	ret = kexec_calculate_store_digests(image);
+	if (ret)
+		goto out;
+
+	for (i = 0; i < image->nr_segments; i++) {
+		struct kexec_segment *ksegment;
+
+		ksegment = &image->segment[i];
+		pr_debug("Loading segment %d: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n",
+			 i, ksegment->buf, ksegment->bufsz, ksegment->mem,
+			 ksegment->memsz);
+
+		ret = kimage_load_segment(image, &image->segment[i]);
+		if (ret)
+			goto out;
+	}
+
+	kimage_terminate(image);
+
+	ret = machine_kexec_post_load(image);
+	if (ret)
+		goto out;
+
+	/*
+	 * Free up any temporary buffers allocated which are not needed
+	 * after image has been loaded
+	 */
+	kimage_file_post_load_cleanup(image);
+exchange:
+	image = xchg(dest_image, image);
+out:
+	if ((flags & KEXEC_FILE_ON_CRASH) && kexec_crash_image)
+		arch_kexec_protect_crashkres();
+
+	kexec_unlock();
+	kimage_free(image);
+	return ret;
+}
+
+static int locate_mem_hole_top_down(unsigned long start, unsigned long end,
+				    struct kexec_buf *kbuf)
+{
+	struct kimage *image = kbuf->image;
+	unsigned long temp_start, temp_end;
+
+	temp_end = min(end, kbuf->buf_max);
+	temp_start = temp_end - kbuf->memsz;
+
+	do {
+		/* align down start */
+		temp_start = temp_start & (~(kbuf->buf_align - 1));
+
+		if (temp_start < start || temp_start < kbuf->buf_min)
+			return 0;
+
+		temp_end = temp_start + kbuf->memsz - 1;
+
+		/*
+		 * Make sure this does not conflict with any of existing
+		 * segments
+		 */
+		if (kimage_is_destination_range(image, temp_start, temp_end)) {
+			temp_start = temp_start - PAGE_SIZE;
+			continue;
+		}
+
+		/* We found a suitable memory range */
+		break;
+	} while (1);
+
+	/* If we are here, we found a suitable memory range */
+	kbuf->mem = temp_start;
+
+	/* Success, stop navigating through remaining System RAM ranges */
+	return 1;
+}
+
+static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end,
+				     struct kexec_buf *kbuf)
+{
+	struct kimage *image = kbuf->image;
+	unsigned long temp_start, temp_end;
+
+	temp_start = max(start, kbuf->buf_min);
+
+	do {
+		temp_start = ALIGN(temp_start, kbuf->buf_align);
+		temp_end = temp_start + kbuf->memsz - 1;
+
+		if (temp_end > end || temp_end > kbuf->buf_max)
+			return 0;
+		/*
+		 * Make sure this does not conflict with any of existing
+		 * segments
+		 */
+		if (kimage_is_destination_range(image, temp_start, temp_end)) {
+			temp_start = temp_start + PAGE_SIZE;
+			continue;
+		}
+
+		/* We found a suitable memory range */
+		break;
+	} while (1);
+
+	/* If we are here, we found a suitable memory range */
+	kbuf->mem = temp_start;
+
+	/* Success, stop navigating through remaining System RAM ranges */
+	return 1;
+}
+
+static int locate_mem_hole_callback(struct resource *res, void *arg)
+{
+	struct kexec_buf *kbuf = (struct kexec_buf *)arg;
+	u64 start = res->start, end = res->end;
+	unsigned long sz = end - start + 1;
+
+	/* Returning 0 will take to next memory range */
+
+	/* Don't use memory that will be detected and handled by a driver. */
+	if (res->flags & IORESOURCE_SYSRAM_DRIVER_MANAGED)
+		return 0;
+
+	if (sz < kbuf->memsz)
+		return 0;
+
+	if (end < kbuf->buf_min || start > kbuf->buf_max)
+		return 0;
+
+	/*
+	 * Allocate memory top down with-in ram range. Otherwise bottom up
+	 * allocation.
+	 */
+	if (kbuf->top_down)
+		return locate_mem_hole_top_down(start, end, kbuf);
+	return locate_mem_hole_bottom_up(start, end, kbuf);
+}
+
+#ifdef CONFIG_ARCH_KEEP_MEMBLOCK
+static int kexec_walk_memblock(struct kexec_buf *kbuf,
+			       int (*func)(struct resource *, void *))
+{
+	int ret = 0;
+	u64 i;
+	phys_addr_t mstart, mend;
+	struct resource res = { };
+
+	if (kbuf->image->type == KEXEC_TYPE_CRASH)
+		return func(&crashk_res, kbuf);
+
+	/*
+	 * Using MEMBLOCK_NONE will properly skip MEMBLOCK_DRIVER_MANAGED. See
+	 * IORESOURCE_SYSRAM_DRIVER_MANAGED handling in
+	 * locate_mem_hole_callback().
+	 */
+	if (kbuf->top_down) {
+		for_each_free_mem_range_reverse(i, NUMA_NO_NODE, MEMBLOCK_NONE,
+						&mstart, &mend, NULL) {
+			/*
+			 * In memblock, end points to the first byte after the
+			 * range while in kexec, end points to the last byte
+			 * in the range.
+			 */
+			res.start = mstart;
+			res.end = mend - 1;
+			ret = func(&res, kbuf);
+			if (ret)
+				break;
+		}
+	} else {
+		for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE,
+					&mstart, &mend, NULL) {
+			/*
+			 * In memblock, end points to the first byte after the
+			 * range while in kexec, end points to the last byte
+			 * in the range.
+			 */
+			res.start = mstart;
+			res.end = mend - 1;
+			ret = func(&res, kbuf);
+			if (ret)
+				break;
+		}
+	}
+
+	return ret;
+}
+#else
+static int kexec_walk_memblock(struct kexec_buf *kbuf,
+			       int (*func)(struct resource *, void *))
+{
+	return 0;
+}
+#endif
+
+/**
+ * kexec_walk_resources - call func(data) on free memory regions
+ * @kbuf:	Context info for the search. Also passed to @func.
+ * @func:	Function to call for each memory region.
+ *
+ * Return: The memory walk will stop when func returns a non-zero value
+ * and that value will be returned. If all free regions are visited without
+ * func returning non-zero, then zero will be returned.
+ */
+static int kexec_walk_resources(struct kexec_buf *kbuf,
+				int (*func)(struct resource *, void *))
+{
+	if (kbuf->image->type == KEXEC_TYPE_CRASH)
+		return walk_iomem_res_desc(crashk_res.desc,
+					   IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY,
+					   crashk_res.start, crashk_res.end,
+					   kbuf, func);
+	else
+		return walk_system_ram_res(0, ULONG_MAX, kbuf, func);
+}
+
+/**
+ * kexec_locate_mem_hole - find free memory for the purgatory or the next kernel
+ * @kbuf:	Parameters for the memory search.
+ *
+ * On success, kbuf->mem will have the start address of the memory region found.
+ *
+ * Return: 0 on success, negative errno on error.
+ */
+int kexec_locate_mem_hole(struct kexec_buf *kbuf)
+{
+	int ret;
+
+	/* Arch knows where to place */
+	if (kbuf->mem != KEXEC_BUF_MEM_UNKNOWN)
+		return 0;
+
+	if (!IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
+		ret = kexec_walk_resources(kbuf, locate_mem_hole_callback);
+	else
+		ret = kexec_walk_memblock(kbuf, locate_mem_hole_callback);
+
+	return ret == 1 ? 0 : -EADDRNOTAVAIL;
+}
+
+/**
+ * kexec_add_buffer - place a buffer in a kexec segment
+ * @kbuf:	Buffer contents and memory parameters.
+ *
+ * This function assumes that kexec_lock is held.
+ * On successful return, @kbuf->mem will have the physical address of
+ * the buffer in memory.
+ *
+ * Return: 0 on success, negative errno on error.
+ */
+int kexec_add_buffer(struct kexec_buf *kbuf)
+{
+	struct kexec_segment *ksegment;
+	int ret;
+
+	/* Currently adding segment this way is allowed only in file mode */
+	if (!kbuf->image->file_mode)
+		return -EINVAL;
+
+	if (kbuf->image->nr_segments >= KEXEC_SEGMENT_MAX)
+		return -EINVAL;
+
+	/*
+	 * Make sure we are not trying to add buffer after allocating
+	 * control pages. All segments need to be placed first before
+	 * any control pages are allocated. As control page allocation
+	 * logic goes through list of segments to make sure there are
+	 * no destination overlaps.
+	 */
+	if (!list_empty(&kbuf->image->control_pages)) {
+		WARN_ON(1);
+		return -EINVAL;
+	}
+
+	/* Ensure minimum alignment needed for segments. */
+	kbuf->memsz = ALIGN(kbuf->memsz, PAGE_SIZE);
+	kbuf->buf_align = max(kbuf->buf_align, PAGE_SIZE);
+
+	/* Walk the RAM ranges and allocate a suitable range for the buffer */
+	ret = arch_kexec_locate_mem_hole(kbuf);
+	if (ret)
+		return ret;
+
+	/* Found a suitable memory range */
+	ksegment = &kbuf->image->segment[kbuf->image->nr_segments];
+	ksegment->kbuf = kbuf->buffer;
+	ksegment->bufsz = kbuf->bufsz;
+	ksegment->mem = kbuf->mem;
+	ksegment->memsz = kbuf->memsz;
+	kbuf->image->nr_segments++;
+	return 0;
+}
+
+/* Calculate and store the digest of segments */
+static int kexec_calculate_store_digests(struct kimage *image)
+{
+	struct crypto_shash *tfm;
+	struct shash_desc *desc;
+	int ret = 0, i, j, zero_buf_sz, sha_region_sz;
+	size_t desc_size, nullsz;
+	char *digest;
+	void *zero_buf;
+	struct kexec_sha_region *sha_regions;
+	struct purgatory_info *pi = &image->purgatory_info;
+
+	if (!IS_ENABLED(CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY))
+		return 0;
+
+	zero_buf = __va(page_to_pfn(ZERO_PAGE(0)) << PAGE_SHIFT);
+	zero_buf_sz = PAGE_SIZE;
+
+	tfm = crypto_alloc_shash("sha256", 0, 0);
+	if (IS_ERR(tfm)) {
+		ret = PTR_ERR(tfm);
+		goto out;
+	}
+
+	desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
+	desc = kzalloc(desc_size, GFP_KERNEL);
+	if (!desc) {
+		ret = -ENOMEM;
+		goto out_free_tfm;
+	}
+
+	sha_region_sz = KEXEC_SEGMENT_MAX * sizeof(struct kexec_sha_region);
+	sha_regions = vzalloc(sha_region_sz);
+	if (!sha_regions) {
+		ret = -ENOMEM;
+		goto out_free_desc;
+	}
+
+	desc->tfm   = tfm;
+
+	ret = crypto_shash_init(desc);
+	if (ret < 0)
+		goto out_free_sha_regions;
+
+	digest = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL);
+	if (!digest) {
+		ret = -ENOMEM;
+		goto out_free_sha_regions;
+	}
+
+	for (j = i = 0; i < image->nr_segments; i++) {
+		struct kexec_segment *ksegment;
+
+#ifdef CONFIG_CRASH_HOTPLUG
+		/* Exclude elfcorehdr segment to allow future changes via hotplug */
+		if (j == image->elfcorehdr_index)
+			continue;
+#endif
+
+		ksegment = &image->segment[i];
+		/*
+		 * Skip purgatory as it will be modified once we put digest
+		 * info in purgatory.
+		 */
+		if (ksegment->kbuf == pi->purgatory_buf)
+			continue;
+
+		ret = crypto_shash_update(desc, ksegment->kbuf,
+					  ksegment->bufsz);
+		if (ret)
+			break;
+
+		/*
+		 * Assume rest of the buffer is filled with zero and
+		 * update digest accordingly.
+		 */
+		nullsz = ksegment->memsz - ksegment->bufsz;
+		while (nullsz) {
+			unsigned long bytes = nullsz;
+
+			if (bytes > zero_buf_sz)
+				bytes = zero_buf_sz;
+			ret = crypto_shash_update(desc, zero_buf, bytes);
+			if (ret)
+				break;
+			nullsz -= bytes;
+		}
+
+		if (ret)
+			break;
+
+		sha_regions[j].start = ksegment->mem;
+		sha_regions[j].len = ksegment->memsz;
+		j++;
+	}
+
+	if (!ret) {
+		ret = crypto_shash_final(desc, digest);
+		if (ret)
+			goto out_free_digest;
+		ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha_regions",
+						     sha_regions, sha_region_sz, 0);
+		if (ret)
+			goto out_free_digest;
+
+		ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha256_digest",
+						     digest, SHA256_DIGEST_SIZE, 0);
+		if (ret)
+			goto out_free_digest;
+	}
+
+out_free_digest:
+	kfree(digest);
+out_free_sha_regions:
+	vfree(sha_regions);
+out_free_desc:
+	kfree(desc);
+out_free_tfm:
+	kfree(tfm);
+out:
+	return ret;
+}
+
+#ifdef CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY
+/*
+ * kexec_purgatory_setup_kbuf - prepare buffer to load purgatory.
+ * @pi:		Purgatory to be loaded.
+ * @kbuf:	Buffer to setup.
+ *
+ * Allocates the memory needed for the buffer. Caller is responsible to free
+ * the memory after use.
+ *
+ * Return: 0 on success, negative errno on error.
+ */
+static int kexec_purgatory_setup_kbuf(struct purgatory_info *pi,
+				      struct kexec_buf *kbuf)
+{
+	const Elf_Shdr *sechdrs;
+	unsigned long bss_align;
+	unsigned long bss_sz;
+	unsigned long align;
+	int i, ret;
+
+	sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
+	kbuf->buf_align = bss_align = 1;
+	kbuf->bufsz = bss_sz = 0;
+
+	for (i = 0; i < pi->ehdr->e_shnum; i++) {
+		if (!(sechdrs[i].sh_flags & SHF_ALLOC))
+			continue;
+
+		align = sechdrs[i].sh_addralign;
+		if (sechdrs[i].sh_type != SHT_NOBITS) {
+			if (kbuf->buf_align < align)
+				kbuf->buf_align = align;
+			kbuf->bufsz = ALIGN(kbuf->bufsz, align);
+			kbuf->bufsz += sechdrs[i].sh_size;
+		} else {
+			if (bss_align < align)
+				bss_align = align;
+			bss_sz = ALIGN(bss_sz, align);
+			bss_sz += sechdrs[i].sh_size;
+		}
+	}
+	kbuf->bufsz = ALIGN(kbuf->bufsz, bss_align);
+	kbuf->memsz = kbuf->bufsz + bss_sz;
+	if (kbuf->buf_align < bss_align)
+		kbuf->buf_align = bss_align;
+
+	kbuf->buffer = vzalloc(kbuf->bufsz);
+	if (!kbuf->buffer)
+		return -ENOMEM;
+	pi->purgatory_buf = kbuf->buffer;
+
+	ret = kexec_add_buffer(kbuf);
+	if (ret)
+		goto out;
+
+	return 0;
+out:
+	vfree(pi->purgatory_buf);
+	pi->purgatory_buf = NULL;
+	return ret;
+}
+
+/*
+ * kexec_purgatory_setup_sechdrs - prepares the pi->sechdrs buffer.
+ * @pi:		Purgatory to be loaded.
+ * @kbuf:	Buffer prepared to store purgatory.
+ *
+ * Allocates the memory needed for the buffer. Caller is responsible to free
+ * the memory after use.
+ *
+ * Return: 0 on success, negative errno on error.
+ */
+static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi,
+					 struct kexec_buf *kbuf)
+{
+	unsigned long bss_addr;
+	unsigned long offset;
+	size_t sechdrs_size;
+	Elf_Shdr *sechdrs;
+	int i;
+
+	/*
+	 * The section headers in kexec_purgatory are read-only. In order to
+	 * have them modifiable make a temporary copy.
+	 */
+	sechdrs_size = array_size(sizeof(Elf_Shdr), pi->ehdr->e_shnum);
+	sechdrs = vzalloc(sechdrs_size);
+	if (!sechdrs)
+		return -ENOMEM;
+	memcpy(sechdrs, (void *)pi->ehdr + pi->ehdr->e_shoff, sechdrs_size);
+	pi->sechdrs = sechdrs;
+
+	offset = 0;
+	bss_addr = kbuf->mem + kbuf->bufsz;
+	kbuf->image->start = pi->ehdr->e_entry;
+
+	for (i = 0; i < pi->ehdr->e_shnum; i++) {
+		unsigned long align;
+		void *src, *dst;
+
+		if (!(sechdrs[i].sh_flags & SHF_ALLOC))
+			continue;
+
+		align = sechdrs[i].sh_addralign;
+		if (sechdrs[i].sh_type == SHT_NOBITS) {
+			bss_addr = ALIGN(bss_addr, align);
+			sechdrs[i].sh_addr = bss_addr;
+			bss_addr += sechdrs[i].sh_size;
+			continue;
+		}
+
+		offset = ALIGN(offset, align);
+
+		/*
+		 * Check if the segment contains the entry point, if so,
+		 * calculate the value of image->start based on it.
+		 * If the compiler has produced more than one .text section
+		 * (Eg: .text.hot), they are generally after the main .text
+		 * section, and they shall not be used to calculate
+		 * image->start. So do not re-calculate image->start if it
+		 * is not set to the initial value, and warn the user so they
+		 * have a chance to fix their purgatory's linker script.
+		 */
+		if (sechdrs[i].sh_flags & SHF_EXECINSTR &&
+		    pi->ehdr->e_entry >= sechdrs[i].sh_addr &&
+		    pi->ehdr->e_entry < (sechdrs[i].sh_addr
+					 + sechdrs[i].sh_size) &&
+		    !WARN_ON(kbuf->image->start != pi->ehdr->e_entry)) {
+			kbuf->image->start -= sechdrs[i].sh_addr;
+			kbuf->image->start += kbuf->mem + offset;
+		}
+
+		src = (void *)pi->ehdr + sechdrs[i].sh_offset;
+		dst = pi->purgatory_buf + offset;
+		memcpy(dst, src, sechdrs[i].sh_size);
+
+		sechdrs[i].sh_addr = kbuf->mem + offset;
+		sechdrs[i].sh_offset = offset;
+		offset += sechdrs[i].sh_size;
+	}
+
+	return 0;
+}
+
+static int kexec_apply_relocations(struct kimage *image)
+{
+	int i, ret;
+	struct purgatory_info *pi = &image->purgatory_info;
+	const Elf_Shdr *sechdrs;
+
+	sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
+
+	for (i = 0; i < pi->ehdr->e_shnum; i++) {
+		const Elf_Shdr *relsec;
+		const Elf_Shdr *symtab;
+		Elf_Shdr *section;
+
+		relsec = sechdrs + i;
+
+		if (relsec->sh_type != SHT_RELA &&
+		    relsec->sh_type != SHT_REL)
+			continue;
+
+		/*
+		 * For section of type SHT_RELA/SHT_REL,
+		 * ->sh_link contains section header index of associated
+		 * symbol table. And ->sh_info contains section header
+		 * index of section to which relocations apply.
+		 */
+		if (relsec->sh_info >= pi->ehdr->e_shnum ||
+		    relsec->sh_link >= pi->ehdr->e_shnum)
+			return -ENOEXEC;
+
+		section = pi->sechdrs + relsec->sh_info;
+		symtab = sechdrs + relsec->sh_link;
+
+		if (!(section->sh_flags & SHF_ALLOC))
+			continue;
+
+		/*
+		 * symtab->sh_link contain section header index of associated
+		 * string table.
+		 */
+		if (symtab->sh_link >= pi->ehdr->e_shnum)
+			/* Invalid section number? */
+			continue;
+
+		/*
+		 * Respective architecture needs to provide support for applying
+		 * relocations of type SHT_RELA/SHT_REL.
+		 */
+		if (relsec->sh_type == SHT_RELA)
+			ret = arch_kexec_apply_relocations_add(pi, section,
+							       relsec, symtab);
+		else if (relsec->sh_type == SHT_REL)
+			ret = arch_kexec_apply_relocations(pi, section,
+							   relsec, symtab);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+/*
+ * kexec_load_purgatory - Load and relocate the purgatory object.
+ * @image:	Image to add the purgatory to.
+ * @kbuf:	Memory parameters to use.
+ *
+ * Allocates the memory needed for image->purgatory_info.sechdrs and
+ * image->purgatory_info.purgatory_buf/kbuf->buffer. Caller is responsible
+ * to free the memory after use.
+ *
+ * Return: 0 on success, negative errno on error.
+ */
+int kexec_load_purgatory(struct kimage *image, struct kexec_buf *kbuf)
+{
+	struct purgatory_info *pi = &image->purgatory_info;
+	int ret;
+
+	if (kexec_purgatory_size <= 0)
+		return -EINVAL;
+
+	pi->ehdr = (const Elf_Ehdr *)kexec_purgatory;
+
+	ret = kexec_purgatory_setup_kbuf(pi, kbuf);
+	if (ret)
+		return ret;
+
+	ret = kexec_purgatory_setup_sechdrs(pi, kbuf);
+	if (ret)
+		goto out_free_kbuf;
+
+	ret = kexec_apply_relocations(image);
+	if (ret)
+		goto out;
+
+	return 0;
+out:
+	vfree(pi->sechdrs);
+	pi->sechdrs = NULL;
+out_free_kbuf:
+	vfree(pi->purgatory_buf);
+	pi->purgatory_buf = NULL;
+	return ret;
+}
+
+/*
+ * kexec_purgatory_find_symbol - find a symbol in the purgatory
+ * @pi:		Purgatory to search in.
+ * @name:	Name of the symbol.
+ *
+ * Return: pointer to symbol in read-only symtab on success, NULL on error.
+ */
+static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
+						  const char *name)
+{
+	const Elf_Shdr *sechdrs;
+	const Elf_Ehdr *ehdr;
+	const Elf_Sym *syms;
+	const char *strtab;
+	int i, k;
+
+	if (!pi->ehdr)
+		return NULL;
+
+	ehdr = pi->ehdr;
+	sechdrs = (void *)ehdr + ehdr->e_shoff;
+
+	for (i = 0; i < ehdr->e_shnum; i++) {
+		if (sechdrs[i].sh_type != SHT_SYMTAB)
+			continue;
+
+		if (sechdrs[i].sh_link >= ehdr->e_shnum)
+			/* Invalid strtab section number */
+			continue;
+		strtab = (void *)ehdr + sechdrs[sechdrs[i].sh_link].sh_offset;
+		syms = (void *)ehdr + sechdrs[i].sh_offset;
+
+		/* Go through symbols for a match */
+		for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) {
+			if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL)
+				continue;
+
+			if (strcmp(strtab + syms[k].st_name, name) != 0)
+				continue;
+
+			if (syms[k].st_shndx == SHN_UNDEF ||
+			    syms[k].st_shndx >= ehdr->e_shnum) {
+				pr_debug("Symbol: %s has bad section index %d.\n",
+						name, syms[k].st_shndx);
+				return NULL;
+			}
+
+			/* Found the symbol we are looking for */
+			return &syms[k];
+		}
+	}
+
+	return NULL;
+}
+
+void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name)
+{
+	struct purgatory_info *pi = &image->purgatory_info;
+	const Elf_Sym *sym;
+	Elf_Shdr *sechdr;
+
+	sym = kexec_purgatory_find_symbol(pi, name);
+	if (!sym)
+		return ERR_PTR(-EINVAL);
+
+	sechdr = &pi->sechdrs[sym->st_shndx];
+
+	/*
+	 * Returns the address where symbol will finally be loaded after
+	 * kexec_load_segment()
+	 */
+	return (void *)(sechdr->sh_addr + sym->st_value);
+}
+
+/*
+ * Get or set value of a symbol. If "get_value" is true, symbol value is
+ * returned in buf otherwise symbol value is set based on value in buf.
+ */
+int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name,
+				   void *buf, unsigned int size, bool get_value)
+{
+	struct purgatory_info *pi = &image->purgatory_info;
+	const Elf_Sym *sym;
+	Elf_Shdr *sec;
+	char *sym_buf;
+
+	sym = kexec_purgatory_find_symbol(pi, name);
+	if (!sym)
+		return -EINVAL;
+
+	if (sym->st_size != size) {
+		pr_err("symbol %s size mismatch: expected %lu actual %u\n",
+		       name, (unsigned long)sym->st_size, size);
+		return -EINVAL;
+	}
+
+	sec = pi->sechdrs + sym->st_shndx;
+
+	if (sec->sh_type == SHT_NOBITS) {
+		pr_err("symbol %s is in a bss section. Cannot %s\n", name,
+		       get_value ? "get" : "set");
+		return -EINVAL;
+	}
+
+	sym_buf = (char *)pi->purgatory_buf + sec->sh_offset + sym->st_value;
+
+	if (get_value)
+		memcpy((void *)buf, sym_buf, size);
+	else
+		memcpy((void *)sym_buf, buf, size);
+
+	return 0;
+}
+#endif /* CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY */